:bug: #227 - fix: fix a bug that prevent the record manager from reas…

[svenvandescheur]

…signing a reviewer when the destruction list is in review

This requires:

• [x] A backend implementation that adds an endpoint to reassign a user
• [x] A frontend change that implements the previously mentioned backend endpoint
• [x] Error handling
• [x] Update current assignee

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 93.19372% with 26 lines in your changes missing coverage. Please review.

Project coverage is 77.62%. Comparing base (ca2f1a1) to head (99813df).

Files	Patch %	Lines
...tructionListAssignees/DestructionListAssignees.tsx	0.00%	13 Missing and 2 partials :warning:
...ructionlist/detail/DestructionListDetail.action.ts	0.00%	4 Missing :warning:
...c/openarchiefbeheer/destruction/api/serializers.py	94.59%	2 Missing :warning:
.../openarchiefbeheer/destruction/assignment_logic.py	96.66%	2 Missing :warning:
...ackend/src/openarchiefbeheer/destruction/models.py	92.85%	2 Missing :warning:
frontend/src/lib/api/destructionLists.ts	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #239 +/- ## ========================================== + Coverage 76.89% 77.62% +0.72% ========================================== Files 193 197 +4 Lines 5653 5864 +211 Branches 106 108 +2 ========================================== + Hits 4347 4552 +205 - Misses 1203 1207 +4 - Partials 103 105 +2 ```

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[svenvandescheur]

@SilviaAmAm

The endpoint now no longer provides error messages when:

• The same user is assigned multiple times
• The author is assigned (as reviewer)

Can you pick this PR up and address the issues (and validate that the frontend shows them correctly)?